1. Field of the Invention
The present invention relates to an image forming apparatus.
2. Description of Related Art
In recent years, a technique of printing a sample image (hereinafter referred to as sample printing) during printing regular images (hereinafter referred to as regular printing) has been used in order to detect quality deterioration (such as density reduction and contamination) of printed matter at the time of printing with a copier and the like, in particular, at the time of printing in a large quantity.
For example, a technique of performing sample printing every predetermined cycle of the number of sheets during regular printing (see, for example, Japanese Patent Application Laid-Open Publication No. Hei 8-197779), and a technique of performing sample printing in response to an instruction from an operator during regular printing (see Japanese Patent Application Laid-Open Publication No. 2004-284323) have been used.
However, when an operator instructs sample printing at arbitrary timing in the case where sample printing at each predetermined cycle of the number of sheets is set, a sample print to be ejected every predetermined cycle of the number of sheets and a sample print to be ejected at the timing instructed by the operator are severally independently processed. Consequently, when the timing of the ejection of the sample print in accordance with the instruction of the operator and the timing of the ejection of the sample print at each predetermined cycle of the number of sheets are short from each other, the sample prints are ejected in series in a short cycle, and one sample print becomes useless. The unnecessary sample printing is thus executed, and the techniques have a problem of poor usability.